It is well-known and appreciated by consumers that fruits and vegetables should be thoroughly washed prior to ingestion in order to remove soils and other unwanted residues which may be undesirably clinging to the surfaces thereof. In addition, some consumers wish to remove the artificial "waxy" coatings which may be applied to some fruits to retard moisture loss for increased storage life and to enhance their appearance. It has been estimated that 95% of consumers recognize the need for thorough washing but, ordinarily, only use tap water for this purpose. On the order of 5% of those consumers who do wash their vegetables use a household cleaner, typically a liquid dishwashing product, to help ensure cleanliness. However, dishwashing products are not specifically intended for such use, inasmuch as they are usually designed to provide high, persistent suds which makes them inconvenient to remove from the fruits or vegetables which have been washed therewith. It will also be appreciated that the formulation of truly effective compositions for washing fruits and vegetables presents a unique problem to the formulator, inasmuch as many art-disclosed cleaning ingredients would, presumably, not be desirable for use in direct contact with foods.
Moreover, it would be desirable to provide effective, toxicologically-acceptable cleaning compositions for fruits and vegetables in the form of low-sudsing, easily rinsable liquid solutions which are water-clear or which have only minimal haziness. Liquid solutions are convenient for the user, since they can be applied directly to soiled fruits and vegetables, followed by rinsing in tap water. The clarity of the liquids connotes cleanliness to the user and is thus highly desirable. Relatively low sudsing is an important attribute so that removal of the solution by rinsing is achieved quickly and easily. It is also of advantage to provide such compositions in the form of stable, low viscosity solutions which can be used in simple pump sprays.
As is well known, many toxicologically-acceptable cleaning ingredients do not meet the aforesaid requirements for clear, low-sudsing, sprayable liquid products. Many detersive surfactants form cloudy or even opaque suspensions in water. Many surfactants are specifically designed to be high sudsing. Still others form relatively high viscosity solutions.
It has now been discovered that certain fatty acids such as oleic acid can be used to provide liquid compositions having the desired properties described above. Unfortunately, when formulated in the desirable basic pH range, such compositions tend to have an undesirable "slick, soapy" feel.
It has now been discovered that certain water-soluble polyethylene glycol (PEG) materials can be used to minimize the undesirably slick, soapy feel of such compositions. Importantly, the PEG materials also unexpectedly reduce the viscosity of the compositions, especially when stored in cold temperatures. Thus, by the practice of this invention, stable, water-clear, low viscosity cleaning compositions having an improved tactile impression can be prepared using safe, food-approved materials.